The army said early on Thursday that 82 rockets had hit Israel during the course of Wednesday and more than 30 were intercepted by Israel's missile defences.

Hamas had rejected initial Egyptian efforts for a full ceasefire, saying it had not been included in the discussions.

The Israeli army announced it would halt its bombardment of Gaza between 10:00am and 3:00pm (0700 to 1200 GMT) on Thursday, following a UN request for a humanitarian truce.

Hamas later followed suit.

"The Palestinian factions agreed to accept the offer from the United Nations for a cooling-down on the ground for five hours starting from 10 in the morning," spokesman Sami Abu Zukhri said.

But in the small hours of Thursday Israeli air strikes continued to shake Gaza and rockets kept flying into Israel, each side said.

Meanwhile, in Cairo, a Hamas official met Egyptian leaders and Palestinian President Mahmud Abbas arrived to join the diplomatic efforts.

US President Barack Obama on Wednesday backed Egypt's efforts to broker a ceasefire, offering Washington's full diplomatic support.

"Over the next 24 hours, we'll continue to stay in close contact with our friends and parties in the region, and we will use all of our diplomatic resources and relationships to support efforts of closing a deal on a ceasefire," The White House said.

Mr Obama said that while he and the world were "heartbroken" by the deaths of civilians in the Gaza Strip, US ally Israel had the "right to defend itself from rocket attacks that terrorise" its population.

In addition to the four children who died on the Gaza seashore, several people were also wounded in an apparent Israeli naval bombardment, medics said.

The first strike scattered terrified children and adults on the beach. A second and third struck as they ran, setting fire to huts on the beach.

The strikes appeared to be the result of shelling by the Israeli navy against an area with small shacks used by fishermen.

Several children ran inside a hotel where at least three had shrapnel injuries.

Several hours after the strikes, the Israeli military described the deaths as "tragic" and said it was investigating the incident.